3D imaging and measurement of transient process based on angularly multiplexing pulsed holographic technique with photopolymers

Multi-frame transient off-axis holographic recording technique based on high repetition frequency nanosecond or picosecond sequential pulsed YAG laser and thick photopolymer holographic recording material was proposed for the 3- D imaging and parameter measurement of high-speed microjet particle field loaded by focused pulse laser. Based on polyvinyl alcohol (PVA)/acrylamide photopolymer with high spatial resolution, high photosensitivity, high diffraction efficiency, good angular selectivity and low volumetric shrinkage, four angularly multiplexed holograms of pulse-laser loaded high-speed microjet particle field with 1 microsecond interval, which corresponded to recording frame frequency of 1 million frames/s, were successfully recorded. The transient process of forming, transforming and breakup of shock wave interface, and the 3-D microjet particle field were clearly reconstructed. The key parameters, such as particle size, number density, velocity, were derived by analyzing the reconstructed 3-D particle fields of transient holograms. We believe that the angularly multiplexing pulsed holographic recording system is expected to have good application prospects in the 3-D imaging and parameter measurement of transient processes such as high-speed microjet particle field, laser-induced plasma, shock wave flow field, etc.